Trump's talk of rigging: What lasting damage to democracy? (part 1)

Trailing in the polls, Donald Trump is raising the spectre of a rigged election. Critics are echoing President Obama’s call for the Republican candidate to "stop whining". Can the election really be rigged? Conspiracy theories aside, there are outside forces at play in this election. In a campaign unlike any other, could there be lasting damage to the United States and its 240-year-old democracy?